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J. YOUNG. TESTING APPARATUS FOR FIRE ALARMS- .No. 402,632. 0 Patented May 7,1889.

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I UNITE 1 STATES PATENT OFFICE.

JOI-IN YOUNG, OF CHICAGOJILLINOIS, ASSIGNOR TO THE WESTERN ELEC- TRIC COMPANY, OF SAME PLACE.

TESTING APPARATUS FOR FIRE-ALARMS.

V SPECIFICATION forming part of Letters Patent No. 402,642, dated May '7, 1889.

7 Application filed November 21, 1884:. Serial No. 148,540. (No model.)

To aZZ whom it may concern.-

Be it known that I, JOHN YOUNG, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Testing Apparatus for Automatic Fire-Alarms, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates .to testing apparatus for automatic fire alarms; and it consists in a circuit extending from the central station through different buildings to circuit-closing mechanism of a clock, and a normally-open ground-circuit, to which the circuit is closed at intervals by the movement of the clock,

' and an annunciator of high resistance included in the circuit at the patrol-station, and a short circuit around said annunciator,which is automatically closed by the falling of the shutter.

The object of my invention is to provide an automatic test at frequent intervals for firealarm circuits which will be reliable, and which will not interfere with the alarms caused by;fire, or give false alarms or indications upon the registering apparatus at the patrol-station.

My invention is illustrated in the accompanying drawings, in which Figure 1 is a diagram of a fire-alarm circuit embodying my invention. Figs..2, 3, and 4: are detailed views of the automatic circuitclosing mechanism of the clock.

As shown in Fig. 1, the fire-alarm circuit a may be traced from the ground at the patrolst'ation through battery b, relay 0, high-resistance annunciator cl, and thence through the rooms of the building and to one side of each of the different thermostats c e, as shown, and thence to the circuit-closing mechanism of the clock. The normally-open ground circuit f extends from the clock to ground.

The clock may be driven by a weight or spring and provided with the usual train of wheels.

Since the ordinary parts of a clock are Well known,I have in Figs. 2, 3, and. 4t illustrated only parts of the circuit-closing mechanism, this being sufficient to make my invention clearly understood. As shown in Fig. 2, the circuit-wire a is connected from one bindingpost of the clock to the contact-spring g. The

normally-open ground-circuit wire f is connected from the other binding-post to the wheel 72, which carries the metallic pin This wheel is normally held by the detent 7c, resting in the notch of the cam Z, as shown more clearly in Figs. 3 and 4.

The clock isregulated so that at stated intervals the lever m is forced against the detent k, lifting detent it from the notch, and the wheel h, being released, is set in motion, the mechanism being operated like the striking mechanism of alarm-clocks. The wheel in its revolution carries the metallic pin 7, against the contact-spring g. The fire-alarm circuit is thus closed for a moment through the clock to the normally-open ground-circuit f. As the wheel h revolves rapidly, the contact between the spring and the pin, though sure, will be but for a moment.

The clock may be regulated so that the wheel will be released at such intervals as may be desired. I have found that once. an

ing the short wire 61, and thus shunting out the resistance of the annunciatoncoil.

The annunciator I have shown and prefer to use is of the form patented to Franklin G. Beach, assignor, in Patent N 0. 245,931, dated August 23,1881. Any other form of circuit closing annunciator may be used to close the circuit as the shutter is thrown down.

The signal-bell and registering apparatus in the local circuit of the relay may be of any known construction, and, since they form no part of the invention, require no further description.

The thermostats consist, preferably, of mercurybulbs, and are adjusted to close the circuit when the mercury is raised by heat to a given point. The local annunciators n and the sig-' nal-boxes 0 may be placed in the circuit and used in the ordinary manner. The resistance of the coil of the annunoiator should be so great that as long as it remains in circuit with the relay by reason of the adjustment of its retractile spring will not operate to close the local circuit, though the main circuit may be closed to ground. It is quite common to adjust relays, so that they will not be operated to close their local circuits While current remains below a certain strength. It thus appears that it is necessary to make the resist ance of the annunciator sufficiently high to cut the current down to such an extent as to prevent the operation of the relay as long as the coils of the annunciator remain in circuit; This resistance of the annunciator is cut out. as soon as the shutter has fallen. By the time the shutter is down the circuit. of the clock will be again open. Thus during themoment that, the circuit is closed through. the clock the resistance of the annunciator. will. remainin circuit, so that the relay and'registering apparatus will not be affected by the momentary closingrof the circuit to the nor- 'an automatic circuit-closin g mechanism operating at stated intervals, a high-resistance annunciator in the circuit at the patrol-station, and a. shunt around said annunciatorcoils closed by the falling of the shutter, substantially as and for the purpose specified.

In Witness whereof I hereunto subscribe my 40 name this 7th day of November, A. ,D. 1884.

J OHN. YOUNG.

\Vitnesses:

GEORGE P. BARTON, E. H. MCCULLOCH; 

